Stephen Harper tells NDP Leader Thomas Mulcair to 'serenity now!'

“A message to Thomas Mulcair after today’s QP: Merry Christmas and serenity now!” reads a Tweet by the Prime Minister, along with a link to a four-second YouTube clip featuring Seinfeld character Frank Costanza screaming “Serenity now!”

The clip is pulled from a 1997 episode from the sitcom where Mr. Costanza, misunderstanding the directions from a relaxation cassette, repeatedly screams the phrase during stressful situations. The Tweet was also forwarded to @AngryTomMulcair, a joke Twitter feed parodying the NDP leader’s hot temper.

The messages are a rare bit of lightness for the Prime Minister’s Twitter feed, which usually consists of political announcements, event commemorations and images from recent photo-ops.

Wednesday’s Question Period, in which Mr. Harper played a larger-than-usual role, became particularly testy over discussions of the F-35 fighter and foreign ownership of Canadian resources, with Mr. Mulcair at one point alleging that the Tories had “sold us out” to Chinese ownership.

Following the exchange, Speaker Andrew Scheer called for increased calm in the House. “Lately, it appears that all sides have, at different times, strayed quite far from the flexibility,accommodation and balance that ideally ought to exist in this place,” he said.